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Oil spill
An oil spill is the release of a liquid petroleum hydrocarbon into the environment due to human activity, and is a form of pollution. The term often refers to marine oil spills, where oil is released into the ocean or coastal waters. The oil may be a variety of materials, including crude oil, refined petroleum products (such as gasoline or diesel fuel) or by-products, ships' bunkers, oily refuse or oil mixed in waste. Spills take months or even years to clean up. Oil is also released into the environment from natural geologic seeps on the sea floor. http://seeps.geol.ucsb.edu/ Most man-made oil pollution comes from land-based activity, but public attention and regulation has tended to focus most sharply on seagoing oil tankers. 16. Petroleum: Oil Spill Environmental effects Studies of Exxon Valdez oil spill have shown that the environmental damage caused by oil spills can be greater than was previously thought. Petroleum-based hydrocarbons can negatively impact marine life at concentrations as low as one part per billion.Long-Term Ecosystem Response to the Exxon Valdez Oil Spill, Science, v.302, 19 December 2003, pp.2082-2085 The lighter fractions of oil, such as benzene and toluene, are highly toxic, but are also volatile and evaporate quickly. Heavier components of crude oil, such as polycyclic aromatic hydrocarbons (PAHs) appear to cause the most damage. While they are less toxic than the lighter volatiles, they persist in the environment much longer. A heavy oil spill can also blanket estuaries and shoreline ecosystems such as salt marshes and tidal pools, preventing gas exchange and blocking light. The oil can mix deeply into pebble, shingle or sandy beaches, where it may remain for months or years. Seabirds are severely affected by spills. The oil penetrates and opens up the structure of their plumage, reducing its insulating ability, and so making the birds more vulnerable to temperature fluctuations and much less buoyant in the water. It also impairs birds' flight abilities, making it difficult or impossible to forage and escape from predators. As they attempt to preen, birds typically ingest oil that coats their feathers, causing kidney damage, altered liver function, and digestive tract irritation. This and the limited foraging ability quickly causes dehydration and metabolic imbalances. Most birds affected by an oil spill die unless there is human intervention.Dunnet, G., Crisp, D., Conan, G., Bourne, W. (1982) "Oil Pollution and Seabird Populations Discussion" Philosophical Transactions of the Royal Society of London. B 297(1087): 413–427Untold Seabird Mortality due to Marine Oil Pollution, Elements Online Environmental Magazine. Marine mammals exposed to oil spills are affected in similar ways as seabirds. Oil coats the fur of Sea otters and seals, reducing its insulation abilities and leading to body temperature fluctuations and hypothermia. Ingestion of the oil causes dehydration and impaired digestion. Largest oil spills ]] '' of the German Navy]] One tonne of crude oil is roughly equal to 308 US gallons, or 7.33 barrels. Estimating the volume of a spill By observing the thickness of the film of oil and its appearance on the surface of the water, it is possible to estimate the quantity of oil spilled. If the surface area of the spill is also known, the total volume of the oil can be calculated.Metcalf & Eddy. Wastewater Engineering, Treatment and Reuse. 4th ed. New York: McGraw-Hill, 2003. 98. Methods of cleaning A sheen is usually dispersed (but not cleaned up) with detergents which makes oil settle to the bottom. Oils that are denser than water, such as Polychlorinated biphenyls (PCBs), can be more difficult to clean as they make the seabed toxic. Methods for cleaning up include: * Bioremediation: use of microorganisms http://www.enviroliteracy.org/article.php/540.html or biological agentshttp://www.epa.gov/oilspill/ncp/bagents.htm to break down or remove oil * Controlled burning can effectively reduce the amount of oil in water, if done properly. But it can only be done in low wind , and can cause air pollution.Oil Spills * Dispersants act as detergents, clustering around oil globules and allowing them to be carried away in the water. This improves the surface aesthetically, and mobilises the oil. Smaller oil droplets, scattered by currents, may cause less harm and may degrade more easily. But the dispersed oil droplets infiltrate into deeper water and can lethally contaminate coral. Recent research indicates that some dispersants are toxic to corals.Barry, Carolyn (2007). Slick Death: Oil-spill treatment kills coral, Science News vol. 172, p. 67. * Watch and wait: in some cases, nautural attentuation of oil may be most appropriate, due to the invasive nature of facilitated methods of remediation, particularly in ecologically sensitive areas. * Dredging: for oils dispersed with detergents and other oils denser than water. * Skimming: Requires calm waters * Solidifying Equipment used includes : * Booms: large floating barriers that round up oil and lift the oil off the water * Skimmers: skim the oil * Sorbents: large sponges that absorb oil * Chemical and biological agents: helps to break down the oil * Vacuums: remove oil from beaches and water surface * Shovels and other road equipments: typically used to clean up oil on beaches Prevention * Secondary containment - methods to prevent releases of oil or hydrocarbons into environment. * Oil Spill Prevention Containment and Countermeasures (SPCC) program by the United States Environmental Protection Agency. * Double hulling - build double hulls into vessels, which reduces the risk and severity of a spill in case of a collision or grounding. Existing single-hull vessels can also be rebuilt to have a double hull. See also References Further reading *''The World Almanac and Book of Facts'', 2004 *''Oil Spill Case Histories 1967-1991'', NOAA/Hazardous Materials and Response Division, Seattle WA, 1992 *''Nelson-Smith, Oil Pollution and Marine Ecology, Elek Scientific, London, 1972; Plenum, New York, 1973 External links * www.black-tides.com An educational website comprising texts, animations, diagrams, quizzes and video clips on oil spills * www.cedre.fr Centre of Documentation, Research and Experimentation on Accidental Water Pollution * International Petroleum Industry Environmental Conservation Association - online publications * International Tanker Owners Pollution Federation * Oil Spill Response and East Asia Response Limited, World's largest oil spill preparedness and response service provider * oil spills and pollution * Newsweek's Black Tides Timeline * How oil spill absorbent products Work * Industrial pollution information from the Coastal Ocean Institute, Woods Hole Oceanographic Institution * IncidentNews.gov - a NOAA site cataloguing major spills, April 14, 2005 * A Google map of the major oil spills since 1960 * A Google Maps Image of a minor oil spill in Libya * Oil spill on Mississippi River after Hurricane Katrina * 2000 Oil spill in Brazil * Japan tanker spills 1.4M gallons of oil * Ashland oil spill in Floreffe, Pennsylvania in 1988 - considered one of the most severe inland oil spills in U.S. history * Oil spill prevention program Category:Oil spills Category:Environmental disasters Category:Hazards de:Ölpest es:Derrame de petróleo fr:Marée noire gl:Maré negra ko:기름 유출 he:התבקעות מכליות נפט nl:Olievlek pt:Maré negra fi:Öljyonnettomuus sv:Oljeutsläpp